WO2009157821A1 - Procédé et agencement de réseau de communication pour effectuer des décisions de transfert - Google Patents

Procédé et agencement de réseau de communication pour effectuer des décisions de transfert Download PDF

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Publication number
WO2009157821A1
WO2009157821A1 PCT/SE2008/050750 SE2008050750W WO2009157821A1 WO 2009157821 A1 WO2009157821 A1 WO 2009157821A1 SE 2008050750 W SE2008050750 W SE 2008050750W WO 2009157821 A1 WO2009157821 A1 WO 2009157821A1
Authority
WO
WIPO (PCT)
Prior art keywords
serving cell
handover
traffic channel
downlink traffic
quality measure
Prior art date
Application number
PCT/SE2008/050750
Other languages
English (en)
Inventor
Jinhua Liu
Rong Hu
Stefan Wager
Original Assignee
Telefonaktiebolaget L M Ericsson (Publ)
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget L M Ericsson (Publ) filed Critical Telefonaktiebolaget L M Ericsson (Publ)
Priority to EP08767216.8A priority Critical patent/EP2294867A4/fr
Priority to US12/999,715 priority patent/US8693360B2/en
Priority to PCT/SE2008/050750 priority patent/WO2009157821A1/fr
Publication of WO2009157821A1 publication Critical patent/WO2009157821A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
    • H04W36/304—Reselection being triggered by specific parameters by measured or perceived connection quality data due to measured or perceived resources with higher communication quality
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0083—Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists
    • H04W36/0085—Hand-off measurements
    • H04W36/0088—Scheduling hand-off measurements

Definitions

  • the present invention relates to a method and arrangement for performing handover decisions in a communication network, in particular in a 3 rd generation telecommunication system including High Speed Downlink Packet Access.
  • each user equipment is allocated a dedicated channel (DPCH) in both directions to exchange higher layer signalling information for example between user equipment and Radio Network Controller (RNC).
  • DPCH dedicated channel
  • F-DPCH Fractional Dedicated Physical Channel
  • the F-DPCH is arranged to carry TPC (Transmit Power Control) commands of several HSDPA users for power control.
  • the channels for TPC commands for the users are time multiplexed in the F-DPCH.
  • the corresponding signalling radio bearers (SRB) arranged to carry radio resource control (RRC) related information when using F-DPCH, are mapped on a High Speed Downlink Shared Channel (HS-DSCH).
  • SRB Signalling radio bearers
  • RRC radio resource control
  • the radio resource control (RRC) related information relates for example to cell change, active set update, RB reconfiguration, etc.
  • the signalling bearers are sent to the user equipment on the High Speed Downlink Shared Channel (HS-DSCH) when F-DPCH is used.
  • HS-DSCH High Speed Downlink Shared Channel
  • this channel does not support soft handover. This can in some cases lead to the situation that the signalling radio bearer can be lost due to poor HS-DSCH reception quality at the user equipment.
  • the uplink quality e.g. for the UL SRB:s, on the other hand, can still be sufficient since both DCH and E-DCH can gain from the benefits of the soft handover operation.
  • the signalling radio bearers can carry vital radio resource control (RRC) related information such as active set update, cell change, radio bearer reconfiguration etc (see for example the document 3GPP TS25.311 : "Radio Resource Control Protocol Specification (FDD)").
  • RRC vital radio resource control
  • FDD Radio Resource Control Protocol Specification
  • WO 2007/025971 discloses a method for executing handover, wherein radio resource messages are bi-casted through both current serving cell and target cell during handover.
  • One object of the present invention is to solve at least some of the problems discussed above so as to ensure signal radio bearer transmission reliability in a communication network, if possible.
  • the method comprises the steps of providing a quality measure related to the shared downlink traffic channel of the serving cell and to the at least one target cell, determining a relation between the quality measure related to the shared downlink traffic channel of the serving cell and the target cell, and performing the handover decision based on said determined relation and based on the size of the provided quality measure related to the shared downlink traffic channel of the serving cell.
  • the handover can be performed before the quality of the shared downlink traffic channel becomes unacceptably low.
  • the acceptable quality for signal radio bearer transmission can be estimated based on for example signal radio bearer transport block size and available power in the serving cell, and thus an adequate estimate for the acceptable quality can be provided.
  • the handover decision step comprises the steps of deciding to perform handover if the determined relation exceeds a predetermined first threshold value, and if said predetermined first threshold value is not exceeded, performing the handover decision also based on the size of the quality measure related to the shared downlink traffic channel of the serving cell.
  • performing the handover decision based on the size of the quality measure related to the shared downlink traffic channel of the serving cell comprises performing a decision not to perform handover if the size of the quality measure related to the shared downlink traffic channel of the serving cell exceeds a predetermined third threshold value. If on the other hand, the quality measure related to the shared downlink traffic channel of the serving cell does not exceed the predetermined third threshold value, the step of performing handover decisions comprises deciding to perform handover if the determined relation exceeds a predetermined second threshold value. The second threshold value is lower than the first threshold value.
  • the step of providing a quality measure related to the shared downlink traffic channel of the serving cell and at the least one target cell comprises in one example providing the quality measure of the serving cell and the target cell from measurement reports from the user equipment.
  • the step of providing a quality measure related to the shared downlink traffic channel of the serving cell and the at least one target cell can also comprise providing the quality measure related to the shared downlink traffic channel of the serving cell and to the target cell from a channel quality indicator (CQI) related to the user equipment.
  • CQI channel quality indicator
  • the present invention also relates to an arrangement for performing handover decisions in a communication network.
  • the arrangement is for example comprised in a radio access network node such as a radio network controller or a radio base station (Node B).
  • the arrangement is comprised in user equipment.
  • Fig 1 shows schematically a communication system.
  • Fig 2 illustrates three cells in the communication systems of Fig 1.
  • Fig 3 is a flow chart illustrating the procedure in the communication system in fig 1 for performing handover decisions.
  • Fig 4 is a block scheme illustrating an arrangement for performing handover decisions in an communication network.
  • the communication system is in the herein described example a 3 rd generation telecommunication system including the feature of High-Speed Downlink Packet Access (HSDPA).
  • HSDPA High-Speed Downlink Packet Access
  • Each user equipment (UE) 160a, ..., 16Od is in accordance with this example allocated a Decicated Physical Channel (DPCH) 170a, ..., 17Od in both the uplink (UL) direction and the downlink direction (DL) so as to exchange higher layer signalling information for example between the user equipment (UE) and the Radio Network Controller (RNC).
  • DPCH Decicated Physical Channel
  • RNC Radio Network Controller
  • a Fractional Dedicated Physical Channel can be used so as to increase capacity by reducing code usage in the DL.
  • the Downlink (DL) Associated Dedicated Physical Channel (A-DPCH) can then be removed.
  • the F-DPCH is arranged to carry TPC (Transmit Power Control) commands of several HSDPA users for power control.
  • the channels for TPC commands for the users are time multiplexed in the F-DPCH.
  • the corresponding signalling radio bearers (SRB) arranged to carry radio resource control (RRC) related information when using F-DPCH, are mapped on a High Speed Downlink Shared Channel (HS-DSCH).
  • the radio resource control (RRC) related information relates for example to cell change, active set update, radio bearer reconfiguration, etc.
  • the signalling radio bearer SRB can be lost due to poor HS-DSCH. Loss of signalling radio bearers can lead to unnecessary SRB retransmissions, call drops and increased delay in scheduling the user in a new HS-DSCH serving cell.
  • HS-DSCH cells 250a, 250b, 250c are depicted, wherein cell A acts as HS-DSCH serving cell for a user equipment 260.
  • the RAN 110 needs to switch the HS- DSCH serving cell to Cell B.
  • This operation is network-controlled.
  • the operation is in one example so controlled that the RNC triggers HS-DSCH serving cell change before DL channel quality of the HS-DSCH serving cell is unacceptably low.
  • the acceptable DL channel quality for SRB transmission can be estimated based on usable SRB transport block size and/or available HS-DSCH power in the HS-DSCH serving cell, which will be described in detail later. There are different ways of measuring the quality of the DL channel.
  • Those cells which are available for the user equipment 260 are defined as an active set (AS). Accordingly, in fig 2 the active set comprises the cells A,B.
  • a procedure 380 performed at the RNC for performing handover decisions comprises the following steps. In a first step 381 , a measure of the DL channel quality of the serving cell is provided. Further, in a second step 382, a corresponding measure of the DL channel quality of the best cell in the active set is provided. On one example, the RNC is arranged to identify the best cell based on the received measurement reports. In one example, the first and second steps 281 , 382 are performed in parallel. In an alternative example, the first and second steps are performed serially in arbitrary order.
  • the measure of the DL channel quality is in one example provided by means of a measurement report received from the user equipments.
  • said measurement reports are provided by means of the uplink channel from the serving cell and the other cells of the active set.
  • the DL channel quality is determined based on Ec/lo and/or RSCP of the Common Pilot Channel (CPICH).
  • the Ec/lo and/or RSCP of the Common Pilot Channel (CPICH) are defined in detail in for example document 3GPP 25.215.
  • CPICH RSCP represents the received signal code power in the Common Pilot Channel.
  • CPICH Ec/lo represents the received signal code power in the Common Pilot Channel divided with the power density in the applicable frequency band.
  • the Node B is arranged to report the Channel Quality Indicator (CQI) (filtered) to the RNC.
  • CQI Channel Quality Indicator
  • Node B is arranged to send the report when the user unit suffers unacceptably low channel quality. This latter method of providing measurement reports is faster and more accurate than the first mentioned method.
  • the channel quality of the serving cell is determined in relation to the channel quality of the best cell.
  • the relation is determined by means of determining a difference between the channel quality of the serving cell and the best cell in the active set (AS) as qbest DCi in As-q S ervi ⁇ g DCi-
  • the determined relation is then compared with a preset value CellChangeThresholdnormai-
  • the preset value is in one example 3 dB.
  • the quality of the serving cell q se rving ceii is determined to be lower than the predetermined quality value qthreshoid, there is a risk that radio signal bearer transmission will fail, and then evaluation proceeds in a fifth step 385.
  • the channel quality of the serving cell is determined in relation to the channel quality of the best cell again.
  • the relation is determined by means of determining a difference between the channel quality of the serving cell and the best cell in the active set (AS) as qbest DCi in As-qserving DCi-
  • the determined relation is then compared with a second preset value CellChangeThreshold SU bnormai-
  • the second preset value is smaller than the first preset value. Therefore, the requirement for triggering a cell changed is lowered if the channel quality has been determined to be low (in fourth step 384).
  • the second preset value is in one example 2 dB. Thus, in one example, it is determined if
  • q re quired is determined in accordance with the following.
  • the RNC is arranged to look up in the HS-DSCH TFC table based on the PDU size of the signal radio bearer so as to find the minimum usable TFC for signal radio bearer transmission and the minimum required SIR for said TFC.
  • the minimum required CPICH Ec/lo for signal radio bearer transmission can then be determined as
  • the arrangement 490 is implemented in software, hardware, or a combination thereof.
  • the arrangement is in one example implemented in the RNC of the RAN.
  • the arrangement is implemented in Node B or a radio base station.
  • the arrangement can also be implemented as a whole or partly in user equipment.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention se rapporte à un procédé et à un agencement destinés à effectuer des décisions de transfert dans un réseau de transmission, les décisions de transfert se rapportant à un équipement utilisateur qui reçoit des données de paquet sur un canal de trafic de liaison descendante partagé en provenance d'une cellule de desserte actuelle. Le procédé comprend les étapes consistant à : fournir (381, 382) une mesure de qualité qui se rapporte au canal de trafic de liaison descendante partagé de la cellule de desserte et à au moins une cellule cible ; déterminer (383) une relation entre la mesure de qualité qui se rapporte au canal de trafic de liaison descendante partagé de la cellule de desserte et la cellule cible ; et effectuer la décision de transfert sur la base de ladite relation déterminée et sur la base de la taille de la mesure de qualité fournie qui se rapporte au canal de trafic de liaison descendante partagé de la cellule de desserte.
PCT/SE2008/050750 2008-06-24 2008-06-24 Procédé et agencement de réseau de communication pour effectuer des décisions de transfert WO2009157821A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP08767216.8A EP2294867A4 (fr) 2008-06-24 2008-06-24 Procédé et agencement de réseau de communication pour effectuer des décisions de transfert
US12/999,715 US8693360B2 (en) 2008-06-24 2008-06-24 Method and arrangement for a communication network for performing handover decisions
PCT/SE2008/050750 WO2009157821A1 (fr) 2008-06-24 2008-06-24 Procédé et agencement de réseau de communication pour effectuer des décisions de transfert

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/SE2008/050750 WO2009157821A1 (fr) 2008-06-24 2008-06-24 Procédé et agencement de réseau de communication pour effectuer des décisions de transfert

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Publication Number Publication Date
WO2009157821A1 true WO2009157821A1 (fr) 2009-12-30

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US (1) US8693360B2 (fr)
EP (1) EP2294867A4 (fr)
WO (1) WO2009157821A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
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WO2012103937A1 (fr) * 2011-02-01 2012-08-09 Nokia Siemens Networks Oy Appareil et procédé pour déterminer si un équipement utilisateur doit être ou non soumis à un transfert intercellulaire

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JP2011055363A (ja) * 2009-09-03 2011-03-17 Fujitsu Ltd 無線通信方法、移動端末、及び無線ネットワーク制御装置
WO2011090328A2 (fr) 2010-01-21 2011-07-28 엘지전자 주식회사 Procédé pour rapporter des résultats concernant une mesure de qualité fondée sur une cellule de référence spécifique dans un système de communication mobile utilisant une agrégation de porteuses, et appareil destiné audit procédé
US8873440B2 (en) * 2010-03-29 2014-10-28 Qualcomm Incorporated Maintaining different virtual active sets for different cell types
US20140036868A1 (en) * 2012-08-03 2014-02-06 Innovative Sonic Corporation Method and apparatus for prioritizing small cells in a wireless communication system
CN105103615B (zh) * 2013-02-06 2020-01-17 爱立信(中国)通信有限公司 对于切换的增强解决方案
EP3361814B1 (fr) * 2015-10-06 2021-02-24 LG Electronics Inc. Procédé et dispositif d'émission/réception de données depuis/vers une station de base dans un système de communication sans fil
US11234170B2 (en) * 2017-03-24 2022-01-25 Convida Wireless, Llc Early handover preparation and early handover command

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WO1995035006A1 (fr) * 1994-06-14 1995-12-21 Nokia Telecommunications Oy Commutations dans un systeme mobile de telecommunications
WO1998037719A1 (fr) * 1997-02-18 1998-08-27 Nokia Telecommunications Oy Transfert entre cellules dans un systeme de communication mobile
EP0966173A1 (fr) * 1998-06-17 1999-12-22 Motorola, Inc. Détermination de transfert dans un système de communication mobile
US20050221828A1 (en) * 1999-09-02 2005-10-06 Tatsuya Wakuta Method and apparatus for performing handoff by varying threshold level
WO2007025970A1 (fr) * 2005-08-30 2007-03-08 Telefonaktiebolaget Lm Ericsson (Publ) Détection des messages de commande pour hsdpa dans un système de communication sans fil

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EP1734779A2 (fr) * 2005-06-14 2006-12-20 Samsung Electronics Co.,Ltd. Procédé d'exécution de transfert dans un système de communication mobile
US8891489B2 (en) * 2007-03-19 2014-11-18 Qualcomm Incorporated Handover mechanism that exploits uplink channel quality of a target cell

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WO1995035006A1 (fr) * 1994-06-14 1995-12-21 Nokia Telecommunications Oy Commutations dans un systeme mobile de telecommunications
WO1998037719A1 (fr) * 1997-02-18 1998-08-27 Nokia Telecommunications Oy Transfert entre cellules dans un systeme de communication mobile
EP0966173A1 (fr) * 1998-06-17 1999-12-22 Motorola, Inc. Détermination de transfert dans un système de communication mobile
US20050221828A1 (en) * 1999-09-02 2005-10-06 Tatsuya Wakuta Method and apparatus for performing handoff by varying threshold level
WO2007025970A1 (fr) * 2005-08-30 2007-03-08 Telefonaktiebolaget Lm Ericsson (Publ) Détection des messages de commande pour hsdpa dans un système de communication sans fil

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012103937A1 (fr) * 2011-02-01 2012-08-09 Nokia Siemens Networks Oy Appareil et procédé pour déterminer si un équipement utilisateur doit être ou non soumis à un transfert intercellulaire

Also Published As

Publication number Publication date
EP2294867A4 (fr) 2014-11-19
US20110096692A1 (en) 2011-04-28
US8693360B2 (en) 2014-04-08
EP2294867A1 (fr) 2011-03-16

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